docs: def search_traceback(self, tb):
          """ Inspect a traceback for new paths to add to our path set."""
          new_paths = []
          with self.lock:
              for filename, line, funcname, txt in traceback.extract_tb(tb):
                  path = os.path.abspath(filename)
                  if path not in self.paths:
                      self.paths.add(path)
                      new_paths.append(path)
          if new_paths:
              self.watch_paths(new_paths)